Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
148
UXUS97 KPUB 041206
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0606 MDT Friday, April 4, 2025
This forecast is for the Air Force Academy for Friday, April 4, 2025:
If the trigger temperature of 36.8 F/2.6 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 0 ft/min (0.0 m/s)
Maximum height of thermals.................. 11894 ft MSL (4273 ft AGL)
Forecast maximum temperature................... 37.0 F/3.2 C
Time of trigger temperature.................... 1200 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Broken/overcast opaque middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 8060 ft MSL (439 ft AGL)
Thermal soaring outlook for Saturday 04/05..... Poor
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:38:13 / 19:25:58 MDT
Total possible sunshine........... 12 hr 47 min 45 sec (767 min 45 sec)
Altitude of sun at 13:02:05 MDT... 57.03 degrees
Upper air data from numerical model forecast valid on 04/04/2025 at 0600 MDT
Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 13845 ft MSL (6224 ft AGL)
Lifted condensation level....... 13333 ft MSL (5712 ft AGL)
Lifted index.................... +5.5
K index......................... +8.0
Height Temperature Wind Wind Spd Lapse Rate ConvectionT Thermal Lift Rate
ft MSL deg C deg F Dir kt m/s C/km F/kft deg C deg F Index fpm m/s
--------------------------------------------------------------------------------
50000 -54.6 -66.3 215 33 17 1.8 1.0 M M M M M
45000 -51.9 -61.4 230 41 21 1.9 1.0 M M M M M
40000 -52.4 -62.3 215 65 33 -0.5 -0.3 M M M M M
38000 -52.6 -62.7 215 75 39 0.7 0.4 M M M M M
36000 -52.1 -61.8 210 84 43 0.6 0.4 M M M M M
34000 -51.8 -61.2 205 92 47 0.8 0.4 M M M M M
32000 -49.7 -57.5 205 94 48 3.7 2.0 M M M M M
30000 -47.5 -53.5 200 95 49 3.9 2.1 M M M M M
29000 -46.0 -50.8 200 90 47 5.3 2.9 20.2 68.4 13.5 M M
28000 -44.4 -47.9 200 85 44 5.3 2.9 18.4 65.2 12.3 M M
27000 -42.8 -45.0 200 79 41 5.3 2.9 16.8 62.3 11.2 M M
26000 -41.0 -41.8 205 73 37 6.8 3.7 15.4 59.8 10.2 M M
25000 -39.0 -38.2 205 66 34 6.8 3.7 14.2 57.6 9.3 M M
24000 -37.0 -34.6 205 59 30 6.8 3.7 13.2 55.8 8.6 M M
23000 -34.9 -30.8 205 52 27 7.1 3.9 12.2 54.0 7.8 M M
22000 -32.8 -27.0 210 47 24 7.1 3.9 11.2 52.1 7.1 M M
21000 -30.2 -22.4 215 41 21 6.9 3.8 10.1 50.2 6.2 M M
20000 -28.5 -19.3 215 35 18 5.5 3.0 8.6 47.5 5.0 M M
19500 -27.7 -17.9 215 32 17 5.5 3.0 7.9 46.2 4.4 M M
19000 -26.9 -16.4 220 29 15 5.5 3.0 7.2 44.9 3.8 M M
18500 -26.1 -15.0 220 27 14 5.6 3.1 6.5 43.7 3.2 M M
18000 -25.0 -13.0 225 25 13 8.7 4.8 6.1 43.0 2.9 M M
17500 -23.7 -10.7 225 25 13 8.4 4.6 5.9 42.6 2.7 M M
17000 -22.4 -8.3 230 25 13 8.9 4.9 5.7 42.3 2.5 M M
16500 -21.1 -6.0 230 24 12 9.0 4.9 5.6 42.0 2.4 M M
16000 -19.7 -3.5 235 24 12 8.8 4.8 5.4 41.8 2.3 M M
15500 -18.4 -1.1 235 22 11 8.7 4.8 5.3 41.5 2.2 M M
15000 -17.1 1.2 235 21 11 8.5 4.6 5.1 41.2 2.0 M M
14500 -15.9 3.4 235 18 9 7.5 4.1 4.8 40.6 1.7 M M
14000 -14.8 5.4 240 14 7 7.5 4.1 4.4 40.0 1.4 M M
13500 -13.7 7.3 240 11 6 7.3 4.0 4.0 39.3 1.0 M M
13000 -12.7 9.1 245 8 4 7.0 3.9 3.6 38.6 0.7 M M
12500 -11.3 11.7 250 6 3 9.3 5.1 3.6 38.4 0.5 M M
12000 -10.3 13.5 265 4 2 7.2 4.0 3.2 37.7 0.1 M M
11750 -9.8 14.4 275 3 2 8.2 4.5 3.0 37.4 -0.1 368 1.9
11500 -9.1 15.6 285 3 1 9.1 5.0 2.9 37.3 -0.2 341 1.7
11250 -8.5 16.7 295 2 1 8.6 4.7 2.8 37.1 -0.2 315 1.6
11000 -7.8 18.0 305 2 1 8.6 4.7 2.8 37.0 -0.3 288 1.5
10750 -7.2 19.0 320 2 1 8.5 4.7 2.7 36.8 -0.4 262 1.3
10500 -6.6 20.1 325 2 1 8.1 4.5 2.6 36.6 -0.6 236 1.2
10250 -6.0 21.2 335 2 1 9.1 5.0 2.4 36.4 -0.7 210 1.1
10000 -5.2 22.6 345 2 1 9.7 5.3 2.4 36.4 -0.7 181 0.9
9750 -4.6 23.7 360 2 1 7.8 4.3 2.4 36.3 -0.7 154 0.8
9500 -4.1 24.6 010 2 1 6.8 3.7 2.2 35.9 -1.0 131 0.7
9250 -3.5 25.7 015 3 1 7.3 4.0 2.0 35.5 -1.2 108 0.5
9000 -3.0 26.6 020 3 1 6.2 3.4 1.8 35.2 -1.4 85 0.4
8750 -2.6 27.3 010 3 2 5.0 2.7 1.4 34.6 -1.7 66 0.3
8500 -2.3 27.9 360 4 2 3.5 1.9 1.0 33.8 -2.1 48 0.2
8250 -2.0 28.4 350 4 2 8.3 4.6 0.6 33.1 -2.5 31 0.2
8000 -1.3 29.7 350 4 2 1.4 0.8 0.5 32.9 -2.6 5 0.0
7750 -2.3 27.9 335 5 2 -23.7 -13.0 -1.1 30.1 -4.3 25 0.1
7500 M M M M M M M M M M M M
7250 M M M M M M M M M M M M
7000 M M M M M M M M M M M M
6750 M M M M M M M M M M M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
04/04/2025 at 0900 MDT | 04/04/2025 at 1200 MDT
|
CAPE... +0.1 LI... +0.1 | CAPE... +36.3 LI... +0.8
CINH... -22.6 K Index... +13.4 | CINH... -1.3 K Index... +12.1
|
Height Temperature Wnd WndSpd Lapse Rate | Temperature Wnd WndSpd Lapse Rate
ft MSL deg C deg F Dir kt m/s C/km F/kft | deg C deg F Dir kt m/s C/km F/kft
--------------------------------------------------------------------------------
50000 -54.2 -65.6 220 32 16 1.7 0.9 | -54.5 -66.1 215 34 18 0.9 0.5
45000 -51.6 -60.9 220 34 18 1.8 1.0 | -53.1 -63.6 215 42 22 0.9 0.5
40000 -51.4 -60.5 210 57 30 -0.0 -0.0 | -50.5 -58.9 215 48 25 1.8 1.0
38000 -51.5 -60.7 210 68 35 -0.3 -0.2 | -49.9 -57.8 210 55 28 -0.8 -0.5
36000 -51.7 -61.1 205 80 41 -0.3 -0.2 | -50.4 -58.7 205 68 35 -0.9 -0.5
34000 -51.9 -61.4 200 91 47 -0.2 -0.1 | -50.9 -59.6 205 81 42 -0.8 -0.4
32000 -50.1 -58.2 200 93 48 3.3 1.8 | -49.5 -57.1 205 81 41 2.6 1.4
30000 -48.2 -54.8 200 94 48 3.6 2.0 | -48.0 -54.4 200 79 40 2.8 1.6
29000 -46.6 -51.9 200 87 45 5.5 3.0 | -46.7 -52.1 200 73 38 4.7 2.6
28000 -45.0 -49.0 200 80 41 5.5 3.0 | -45.3 -49.5 200 68 35 4.7 2.6
27000 -43.3 -45.9 200 72 37 5.5 3.0 | -43.9 -47.0 195 62 32 4.8 2.6
26000 -41.5 -42.7 200 65 34 7.1 3.9 | -42.0 -43.6 195 57 29 8.3 4.6
25000 -39.4 -38.9 205 60 31 7.1 3.9 | -39.5 -39.1 200 54 28 8.3 4.5
24000 -37.2 -35.0 205 54 28 7.1 3.9 | -37.0 -34.6 200 51 26 8.3 4.5
23000 -35.0 -31.0 205 49 25 7.6 4.2 | -34.8 -30.6 205 46 24 6.0 3.3
22000 -32.8 -27.0 205 46 24 7.6 4.2 | -33.0 -27.4 210 39 20 6.1 3.3
21000 -29.9 -21.8 210 42 22 7.0 3.9 | -30.7 -23.3 220 30 16 6.1 3.4
20000 -28.5 -19.3 215 33 17 4.6 2.5 | -28.9 -20.0 215 24 12 6.2 3.4
19500 -27.8 -18.0 215 28 15 4.6 2.5 | -27.9 -18.2 210 20 10 6.2 3.4
19000 -27.1 -16.8 220 24 12 4.7 2.6 | -27.0 -16.6 200 17 9 6.2 3.4
18500 -26.4 -15.5 225 19 10 5.2 2.9 | -26.1 -15.0 195 15 7 6.6 3.6
18000 -25.3 -13.5 225 17 9 9.0 4.9 | -24.9 -12.8 190 14 7 8.9 4.9
17500 -24.0 -11.2 220 16 8 8.8 4.8 | -23.6 -10.5 185 13 7 8.9 4.9
17000 -22.7 -8.9 220 15 8 8.0 4.4 | -22.4 -8.3 185 13 7 7.1 3.9
16500 -21.5 -6.7 220 13 7 8.0 4.4 | -21.4 -6.5 180 11 6 7.0 3.8
16000 -20.3 -4.5 220 12 6 7.9 4.3 | -20.3 -4.5 170 9 5 7.1 3.9
15500 -19.2 -2.6 220 9 5 7.8 4.3 | -19.3 -2.7 160 8 4 7.1 3.9
15000 -18.0 -0.4 225 6 3 7.5 4.1 | -18.2 -0.8 145 6 3 7.5 4.1
14500 -16.9 1.6 205 3 2 6.9 3.8 | -17.0 1.4 125 7 4 8.4 4.6
14000 -15.9 3.4 130 2 1 7.1 3.9 | -15.8 3.6 115 9 4 7.9 4.4
13500 -14.8 5.4 090 4 2 7.6 4.2 | -14.8 5.4 100 10 5 5.8 3.2
13000 -13.8 7.2 075 6 3 7.9 4.3 | -14.0 6.8 090 11 5 6.1 3.3
12500 -12.3 9.9 070 7 4 9.8 5.4 | -12.9 8.8 085 12 6 7.1 3.9
12000 -11.1 12.0 065 9 5 8.4 4.6 | -12.0 10.4 070 12 6 5.8 3.2
11750 -10.4 13.3 060 10 5 8.2 4.5 | -11.6 11.1 065 13 7 5.3 2.9
11500 -9.8 14.4 060 10 5 8.3 4.5 | -11.2 11.8 055 13 7 5.2 2.8
11250 -9.2 15.4 055 11 6 9.0 4.9 | -10.8 12.6 050 14 7 5.7 3.1
11000 -8.5 16.7 055 12 6 8.7 4.8 | -10.4 13.3 040 15 8 5.5 3.0
10750 -7.9 17.8 050 13 7 7.3 4.0 | -10.1 13.8 030 17 9 4.6 2.5
10500 -7.4 18.7 050 13 7 6.3 3.4 | -9.7 14.5 025 19 10 3.9 2.2
10250 -6.9 19.6 045 14 7 8.1 4.4 | -9.4 15.1 015 21 11 5.5 3.0
10000 -6.3 20.7 045 14 7 8.0 4.4 | -8.9 16.0 015 23 12 7.4 4.0
9750 -5.8 21.6 040 14 7 5.8 3.2 | -8.4 16.9 015 24 12 7.3 4.0
9500 -5.4 22.3 035 14 7 4.7 2.6 | -7.9 17.8 010 24 12 6.6 3.6
9250 -5.0 23.0 035 14 7 7.8 4.3 | -7.4 18.7 010 24 13 9.3 5.1
9000 -4.4 24.1 030 13 7 7.7 4.2 | -6.6 20.1 010 24 12 10.7 5.9
8750 -4.0 24.8 020 13 7 4.7 2.6 | -5.9 21.4 010 23 12 9.2 5.0
8500 -3.6 25.5 010 14 7 5.6 3.1 | -5.2 22.6 010 22 11 9.5 5.2
8250 -3.2 26.2 005 14 7 4.8 2.6 | -4.5 23.9 010 21 11 9.9 5.4
8000 -2.7 27.1 005 14 7 11.6 6.3 | -3.6 25.5 010 20 10 16.6 9.1
7750 -1.4 29.5 360 13 7 24.2 13.3 | -2.0 28.4 010 17 9 25.9 14.2
7500 M M M M M M M | M M M M M M M
7250 M M M M M M M | M M M M M M M
7000 M M M M M M M | M M M M M M M
6750 M M M M M M M | M M M M M M M
04/04/2025 at 1500 MDT | 04/04/2025 at 1800 MDT
|
CAPE... +105.2 LI... +1.0 | CAPE... +22.8 LI... +2.8
CINH... -0.1 K Index... +10.4 | CINH... -1.9 K Index... +8.9
|
Height Temperature Wnd WndSpd Lapse Rate | Temperature Wnd WndSpd Lapse Rate
ft MSL deg C deg F Dir kt m/s C/km F/kft | deg C deg F Dir kt m/s C/km F/kft
--------------------------------------------------------------------------------
50000 -54.4 -65.9 225 33 17 1.1 0.6 | -54.2 -65.6 225 26 13 1.3 0.7
45000 -52.8 -63.0 215 42 22 1.1 0.6 | -52.2 -62.0 225 36 18 1.4 0.7
40000 -51.3 -60.3 210 46 24 1.0 0.5 | -51.8 -61.2 210 42 21 0.2 0.1
38000 -50.7 -59.3 210 51 26 0.5 0.3 | -51.5 -60.7 205 46 24 1.0 0.6
36000 -50.4 -58.7 210 63 32 0.5 0.3 | -50.9 -59.6 210 53 27 1.0 0.6
34000 -50.2 -58.4 210 75 38 0.5 0.3 | -50.3 -58.5 210 60 31 1.0 0.6
32000 -49.3 -56.7 210 78 40 1.6 0.9 | -49.5 -57.1 210 62 32 1.3 0.7
30000 -48.3 -54.9 205 81 41 2.1 1.2 | -48.7 -55.7 210 64 33 1.7 0.9
29000 -46.9 -52.4 205 78 40 5.5 3.0 | -47.5 -53.5 215 57 29 4.6 2.5
28000 -45.2 -49.4 205 74 38 5.5 3.0 | -46.2 -51.2 220 49 25 4.5 2.5
27000 -43.6 -46.5 205 70 36 5.5 3.0 | -44.8 -48.6 225 42 22 4.6 2.5
26000 -41.6 -42.9 205 65 33 7.8 4.3 | -42.9 -45.2 225 36 18 8.5 4.6
25000 -39.3 -38.7 205 57 30 7.8 4.3 | -40.4 -40.7 230 32 16 8.5 4.6
24000 -37.0 -34.6 215 50 26 7.8 4.3 | -37.8 -36.0 235 28 14 8.5 4.6
23000 -34.7 -30.5 215 43 22 7.5 4.1 | -34.6 -30.3 235 24 13 8.5 4.7
22000 -32.4 -26.3 220 36 19 7.5 4.1 | -32.1 -25.8 235 23 12 8.5 4.7
21000 -29.6 -21.3 225 28 14 7.1 3.9 | -29.6 -21.3 235 22 11 8.2 4.5
20000 -27.9 -18.2 220 21 11 5.6 3.1 | -27.3 -17.1 230 20 10 7.3 4.0
19500 -27.0 -16.6 215 19 10 5.7 3.1 | -26.3 -15.3 225 19 10 7.3 4.0
19000 -26.2 -15.2 210 16 8 5.7 3.1 | -25.2 -13.4 220 18 9 7.3 4.0
18500 -25.3 -13.5 200 13 7 6.1 3.3 | -24.1 -11.4 220 17 9 7.1 3.9
18000 -24.3 -11.7 195 13 7 8.0 4.4 | -23.1 -9.6 215 16 8 6.5 3.5
17500 -23.1 -9.6 195 13 7 8.0 4.4 | -22.1 -7.8 205 14 7 6.4 3.5
17000 -21.9 -7.4 195 13 7 7.3 4.0 | -21.1 -6.0 200 14 7 7.3 4.0
16500 -20.9 -5.6 190 13 7 7.3 4.0 | -20.0 -4.0 190 14 7 7.3 4.0
16000 -19.8 -3.6 185 12 6 6.2 3.4 | -18.9 -2.0 185 14 7 7.4 4.1
15500 -19.0 -2.2 180 10 5 5.5 3.0 | -17.8 -0.0 185 13 7 7.4 4.1
15000 -18.2 -0.8 170 7 4 5.6 3.1 | -16.7 1.9 185 11 6 6.5 3.5
14500 -17.4 0.7 150 6 3 5.8 3.2 | -16.0 3.2 185 10 5 4.6 2.5
14000 -16.5 2.3 125 6 3 6.1 3.3 | -15.3 4.5 180 8 4 4.2 2.3
13500 -15.5 4.1 095 6 3 7.4 4.1 | -14.9 5.2 170 5 3 2.4 1.3
13000 -14.4 6.1 070 7 4 7.3 4.0 | -14.5 5.9 135 3 1 2.8 1.5
12500 -13.3 8.1 055 9 5 6.9 3.8 | -14.0 6.8 055 4 2 5.1 2.8
12000 -12.4 9.7 035 14 7 6.5 3.6 | -13.2 8.2 035 9 5 5.5 3.0
11750 -11.9 10.6 030 16 8 6.0 3.3 | -12.8 9.0 030 11 6 5.5 3.0
11500 -11.5 11.3 030 18 9 5.9 3.2 | -12.4 9.7 030 13 7 5.5 3.0
11250 -11.0 12.2 030 20 10 7.4 4.1 | -12.0 10.4 025 15 8 5.8 3.2
11000 -10.4 13.3 030 23 12 7.5 4.1 | -11.5 11.3 025 18 9 5.8 3.2
10750 -10.0 14.0 030 24 12 6.0 3.3 | -11.1 12.0 025 20 11 5.5 3.0
10500 -9.5 14.9 030 25 13 4.8 2.7 | -10.7 12.7 025 22 11 5.2 2.9
10250 -9.1 15.6 030 25 13 8.2 4.5 | -10.3 13.5 030 24 12 6.3 3.5
10000 -8.4 16.9 025 25 13 10.2 5.6 | -9.8 14.4 030 26 13 7.1 3.9
9750 -7.7 18.1 025 25 13 8.2 4.5 | -9.3 15.3 025 27 14 6.5 3.6
9500 -7.1 19.2 025 24 13 7.8 4.3 | -8.8 16.2 025 28 14 6.6 3.6
9250 -6.6 20.1 025 24 12 9.9 5.4 | -8.3 17.1 020 30 15 6.3 3.5
9000 -5.7 21.7 020 23 12 11.2 6.1 | -7.8 18.0 020 31 16 8.0 4.4
8750 -5.0 23.0 020 22 11 9.8 5.4 | -7.2 19.0 015 29 15 9.5 5.2
8500 -4.2 24.4 020 21 11 10.5 5.8 | -6.5 20.3 015 28 14 9.1 5.0
8250 -3.5 25.7 020 21 11 9.0 5.0 | -5.8 21.6 015 26 14 9.3 5.1
8000 -2.7 27.1 020 20 10 14.6 8.0 | -5.1 22.8 010 25 13 11.9 6.5
7750 -1.1 30.0 020 18 9 27.9 15.3 | -4.0 24.8 010 20 11 15.7 8.6
7500 M M M M M M M | M M M M M M M
7250 M M M M M M M | M M M M M M M
7000 M M M M M M M | M M M M M M M
6750 M M M M M M M | M M M M M M M
________________________________________________________________________________
This product is issued twice per day, once by approximately 0630 MST/0730 MDT
(1330 UTC). It is not continuously monitored nor updated after its initial
issuance.
The information contained herein is based on rawinsonde observation and/or
numerical weather prediction model data taken near the Air Force Academy
in Colorado Springs, Colorado at
North Latitude: 38 deg 58 min 48.000 sec
West Longitude: 104 deg 49 min 12.000 sec
Elevation: 6572 feet (2003 meters)
and may not be representative of other areas along the Front Range of the
Colorado Rocky Mountains. Note that some elevations in numerical weather
prediction models differ from actual station elevations, which can lead to
data which appear to be below ground. Erroneous data such as these should
not be used.
The content and format of this report as well as the issuance times are subject
to change without prior notice. Comments and suggestions are welcome and should
be directed to one of the addresses or phone numbers shown at the bottom of this
page. To expedite a response to comments, be sure to mention your interest in
the soaring forecast.
DEFINITIONS:
CAPE (Convective Available Potential Energy) - An integrated measure of the
energy available for convective development, also known as the positive
area on a thermodynamic diagram. Units are Joules per kilogram. Larger
values are indicative of greater instability and the possibility of
stronger convective activity, including thunderstorms. Values around or
greater than 1000 suggest the possibility of severe weather should
convective activity develop.
CIN (Convective Inhibition) - An integrated measure of the amount of energy
needed to initiate convective activity, also known as the negative area on
a thermodynamic diagram. Units are Joules per kilogram. The more negative
this number, the more energy is required to initiate convection. This
inhibitive energy can be overcome through surface heating, cooling aloft,
lifting mechanisms (orographic, frontal, gravity waves, etc.)
Convective Condensation Level - The height to which an air parcel possessing the
average saturation mixing ratio in the lowest 4000 feet of the airmass,
if heated sufficiently from below, will rise dry adiabatically until it
just becomes saturated. It estimates the base of cumulus clouds that are
produced by surface heating only.
Convection Temperature (ConvectionT) - The surface temperature required to make
the airmass dry adiabatic up to the given level. It can be considered a
"trigger temperature" for that level.
Freezing Level - The height where the temperature is zero degrees Celsius.
Height of Stable Layer - The height (between 12,000 and 18,000 feet above
mean sea level) where the smallest lapse rate exists. The location and
existence of this feature is important in the generation of mountain
waves.
K Index - A measure of stability which combines the temperature difference
between approximately 5,000 and 18,000 feet above the surface, the amount
of moisture at approximately 5,000 feet above the surface, and a measure
of the dryness at approximately 10,000 feet above the surface. Larger
positive numbers indicate more instability and a greater likelihood of
thunderstorm development. One interpretation of K index values regarding
soaring in the western United States is given in WMO Technical Note 158
and is reproduced in the following table:
below -10 no or weak thermals
-10 to 5 dry thermals or 1/8 cumulus with moderate thermals
5 to 15 good soaring conditions
15 to 20 good soaring conditions with occasional showers
20 to 30 excellent soaring conditions, but increasing
probability of showers and thunderstorms
above 30 more than 60 percent probability of thunderstorms
Lapse Rate - The change with height of the temperature. Negative values indicate
inversions.
Lifted Condensation Level - The height to which an air parcel possessing the
average dew point in the lowest 4000 feet of the airmass and the forecast
maximum temperature must be lifted dry adiabatically to attain saturation.
Lifted Index (LI) - The difference between the environmental temperature at a
level approximately 18,000 feet above the surface and the temperature of
an air parcel lifted dry adiabatically from the surface to its lifted
condensation level and then pseudoadiabatically thereafter to this same
level. The parcel`s initial temperature is the forecast maximum
temperature and its dew point is the average dew point in the lowest 4000
feet of the airmass. Negative values are indicative of instability with
positive values showing stable conditions.
Lift Rate - An experimental estimate of the strength of thermals. It is
computed the same way as the maximum rate of lift but uses the actual
level rather than the maximum height of thermals in the calculation.
Also, none of the empirical adjustments based on cloudiness and K-index
are applied to these calculations.
Maximum Height of Thermals - The height where the dry adiabat through the
forecast maximum temperature intersects the environmental temperature.
Maximum Rate of Lift - An estimate of the maximum strength of thermals. It
is computed from an empirical formula which combines the expected maximum
height of thermals with the difference in the environmental temperatures
between the maximum height of thermals and the temperature 4,000 feet
above the ground. After this computation, further empirical adjustments
are made based on the value of the K-index and the amount and opacity of
middle and high level cloudiness expected between the time of trigger
temperature and the time of overdevelopment.
Middle/High Clouds - The amount and opacity of middle (altostratus, altocumulus)
or high (cirrus, cirrostratus, cirrocumulus) clouds. Broken means that
between 60% and 90% of the sky is covered by the cloud, with overcast
conditions occurring when more than 90% of the sky is covered by the cloud.
Thin implies that the clouds are predominantly transparent, meaning that
some sunlight is reaching the ground, in contrast to opaque which suggests
that little sunlight is reaching the ground.
Potential Height of Wave - The minimum of the following two heights:
1. Level above the height of stable layer (or 14,000 feet if none exists)
where the wind direction changes by 30 degrees or more
2. Level above the height of stable layer (or 14,000 feet if none exists)
where the wind speed no longer increases with height
PVA/NVA - Positive vorticity advection (PVA)/negative vorticity advection (NVA)
on the 500 millibar isobaric surface (approximately 18,000 feet above mean
sea level). Weak PVA has been shown to assist in mountain wave soaring.
Soaring Window - The time between the time the trigger temperature is reached
and the time of overdevelopment.
Thermal Index - The difference between the environmental temperature and the
temperature at a particular level determined by following the dry adiabat
through the forecast maximum temperature up to that level. Negative values
are indicative of thermal lift.
Thermal Soaring Index - An adjective rating (for sailplanes) based on the
computed maximum rate of lift, and the wind speed and middle and high
cloud cover expected during the soaring window (the time of the trigger
temperature and the time of overdevelopment) according to the following:
Maximum rate of lift Adjective Rating
>= 800 fpm Excellent
>= 400 and < 800 fpm Good
>= 200 and < 400 fpm Fair
< 200 fpm Poor
Time of Overdevelopment - The time one or more of the following phenomena,
which essentially shut off thermal lift, is expected to occur:
1. formation of broken to overcast convective cloud cover
2. formation of scattered to numerous downbursts
3. initiation of widespread precipitation
Time of Trigger Temperature - The time the surface temperature is expected to
reach the trigger temperature.
Trigger Temperature - The surface temperature required to make the first 4000
feet of the atmosphere dry adiabatic.
Wave Soaring Index - An empirical, adjective rating (for sailplanes) which
attempts to combine a variety of phenomena important in mountain wave
soaring into a single index number. Objective points are assigned to
these phenomena: wind speed and direction at 14,000 ft MSL, the static
stability in the 12,000-18,000 ft MSL layer, the wind speed gradient above
the stable layer, jet stream location and frontal and upper trough
movements.
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